Goh Miyamoto

Autonomous and Decentralized Optimization of Large-Scale Heterogeneous Wireless Networks by Neural Network Dynamics

We propose a neurodynamical approach to a large-scale optimization problem in Cognitive Wireless Clouds, in which a huge number of mobile terminals with multiple different air interfaces autonomously utilize the most appropriate infrastructure wireless networks, by sensing available wireless networks, selecting the most appropriate one, and reconfiguring themselves with seamless handover to the target networks. To deal with such a cognitive radio network, game theory has been applied in order to analyze the stability of the dynamical systems consisting of the mobile terminals distributed behaviors, but it is not a tool for globally optimizing the state of the network. As a natural optimization dynamical system model suitable for large-scale complex systems, we introduce the neural network dynamics which converges to an optimal state since its property is to continually decrease its energy function. In this paper, we apply such neurodynamics to the optimization problem of radio access technology selection. We compose a neural network that solves the problem, and we show that it is possible to improve total average throughput simply by using distributed and autonomous neuron updates on the terminal side.

IEEE 1900.4 WG on architecture and enablers for optimized radio & spectrum resource usage

In general, cognitive radio system (CRS) can be viewed as a radio system using technology that allows it to obtain knowledge of its operational environment, established policies and its internal state; dynamically and autonomously adjust its operational parameters and protocols according to the obtained knowledge and predefined objectives; and to learn from the results obtained. Given such definition many use cases and business cases are possible, including heterogeneous type CRS, spectrum sharing type CRS, and dynamic spectrum assignment type CRS. As a result, several standardization activities have been performed recently to enable such use cases and exploit the corresponding business opportunities. One of such standardization has been performed within the IEEE 1900.4 Working Group (WG) on “Architecture and Enablers for Optimized Radio & Spectrum Resource Usage.” In February 2009, the first IEEE standard defining CRS has been published originating from the IEEE 1900.4 WG and entitled “Architectural Building Blocks Enabling Network-Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access Networks.” This paper gives technical overview of this standard. Also, it describes ongoing activities in the IEEE 1900.4 WG aimed at developing two draft standards: P1900.4.1 for “Interfaces and Protocols Enabling Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Networks” and P1900.4a for “Architecture and Interfaces for Dynamic Spectrum Access Networks in White Space Frequency Bands.”1

IEEE draft standards P1900.4.1 and P1900.4a for heterogeneous type and spectrum sharing type cognitive radio systems

The current radio operational environment is characterized by its heterogeneity, which includes multiple operators, services, radio access technologies, network topologies, radio equipment, and frequency bands. While each radio access technology has mechanisms for efficient usage of the assigned spectrum, there is a need for the new intelligent management system, which can have capability to optimize spectrum usage across different radio access technologies and operators. In IEEE the standardization of such new management system has been performed under the Working Group 1900.4 of the Standards Coordinating Committee 41. The IEEE standard 1900.4 Architectural Building Blocks Enabling Network-Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access Networks was published in February 2009. Currently, two more projects are active in Working Group 1900.4. The first project is P1900.4.1 Interfaces and Protocols Enabling Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Networks. The second project is P1900.4a Architecture and Interfaces for Dynamic Spectrum Access Networks in White Space Frequency Bands. The purpose of this paper is to give overview of the current status of the IEEE projects P1900.4.1 and P1900.4a.1

IEEE 1900.4 generic procedures to realize Dynamic Spectrum Access use cases

IEEE 1900.4 standard defines management system to support network-terminal distributed optimization of radio resource usage and improvement in quality-of-service in heterogeneous wireless networks. In particular the standard defines system and functional requirements, system and functional architecture, information model, and generic procedures. An informative part of the standard describes use cases and deployment examples. This paper gives a comprehensive overview of the generic procedures of IEEE 1900.4 standard.

Large-scale Hybrid Testbed for Cognitive Radio Networks by Real-and-Virtual Execution

Cognitive-radio networks are intended to be future spectrum-efficient systems that can adapt to their operating environments by extending software defined radio (SDR) technologies. A testbed system for cognitive radio needs to be able to deal with sensitive radio components to verify low-level protocols and functions on CR terminals, and to evaluate high-level network protocols and throughputs using various applications running on a large wireless network. We propose a testbed for cognitve-radio networks under which terminals communicate using both real CR devices and those virtually configured in the sensing environment. All the stacks from MAC/PHY to the application layer are programmable and conform to the common interface of the simulation/emulation environment for CR networks, called CWC-EF. The physical layer is either configured as a real CR device or as a virtual module with a cognitive component either by sensing real spectra or time-driven radio-feature extracted data that are generated from radio data. A real-device approach is used to verify the radio configuration and a virtual configuration is used to evaluate the network as many CR terminals are expected to be utilized. The testbed is flexible enough to re-build CR functions and protocols under any spectrum-sensing environment. CWC-EF is also intended to be used not only by local users but also remote users via the Internet.